Central venous catheters (CVCs) are used in critical care situations to provide direct access to a patient's blood stream. A typical CVC includes an elongated flexible distal tube having a plurality of independent lumens extending longitudinally therethrough. Commonly used CVC's have three such internal lumens. A distal terminus of the flexible tube is adapted for placement directly in a patient's vein. The lumens open at this distal terminus. At the proximal end of the catheter, the lumens are split or Y'd into three independent flexible proximal tubes. These tubes each have an independent proximal-end injection/withdrawal port. Each such port typically includes a needle-less connector such as a Luer-lok connector. In common use, the connector is connected to a mating piece having a pierceable rubber membrane. To inject or withdraw fluid through a CVC lumen, a syringe is used, with its needle inserted into the mating piece through the rubber membrane. In some cases, syringes are connected directly to the CVC connector without a needle, thereby eliminating the need for the pierceable membrane. Each of the three catheter lumens can be independently accessed for injecting fluids into or withdrawing fluids from a patient's blood stream. An example of a CVC is shown in U.S. Pat. No. 4,894,057, which is hereby incorporated by reference.
The distal end of the CVC is inserted by a surgical procedure in a vein close to the heart. The distal tube of the catheter extends through the patient's skin. The skin entry point is sutured, dressed, and carefully monitored to avoid infections. With proper attention and care, a CVC can be left in place for relatively long times, such as days or months. Unfortunately, CVC problems are frequent, resulting in the need for frequent replacement. Most of these problems are the result of mistakes, inattentiveness, or carelessness on the part of medical personnel, and could be prevented with more careful adherence to proper procedures. While a CVC can be replaced, each such replacement requires an expensive surgical procedure and presents an unnecessary health risk to the patient.
Blood and fibrin clotting within a CVC lumen is one problem which frequently mandates CVC replacement. CVC lumens are normally kept free from clots when not in use by injecting a heparin solution into them. This is commonly referred to as a heparin lock. Heparin is a protein material which acts as a blood anti-coagulant. A heparin lock must be established in each catheter lumen immediately after CVC installation, and must be re-established after each CVC access. Failure to properly establish and maintain a heparin lock in each catheter lumen is a common cause of CVC failure and replacement.
Establishing a heparin lock is a seemingly simple procedure. Nevertheless, a lengthy sequence of steps are required, involving several different pieces of equipment. Establishing a heparin lock in a single CVC lumen, for example, requires at least the following steps. First, a nurse cleans the appropriate pierceable membrane with alcohol and/or Betadine. Next, the nurse withdraws saline into a hypodermic needle, and subsequently injects the saline into the CVC lumen, through the pierceable membrane. Finally, heparin is withdrawn into another hypodermic needle and injected into the CVC lumen.
For a triple-lumen CVC, this procedure must be repeated three times. Six different hypodermic needles and corresponding injections are needed, and there are numerous opportunities for mistakes. A mistake with any single CVC lumen can require replacement of the entire CVC.
As an additional complication, each access to a CVC by needle gives rise to a potential source of injury and infection to the care-giver through contact with the needle. This is particularly important when the patient being treated has a dangerous infection, such as HIV or hepatitis. Often, the care-giver and patient are unaware that an infection is present.
It has been observed that a surprisingly high percentage of CVC failures are the result of mistakes made during initial installation of the CVCs. This can be attributed in large part to the great number of steps required to initialize and establish heparin locks in the individual lumens of multi-lumen CVCs. Another reason for these mistakes is that the various solutions and syringes needed to perform CVC initialization are often supplied separately. A nurse must often collect these materials from different places. This can be a costly and time consuming process. Even if proper equipment is provided, it is often not designed to work together as a system.
The invention described below is a system for conveniently performing initial CVC saline flushing and anti-coagulant injection to properly establish heparin locks in each lumen of a multi-lumen CVC immediately after surgical insertion of the CVC. The invention reduces the amount of equipment which must be found and used, and greatly simplifies the entire CVC initialization process. As a result, mistakes and CVC failures are greatly reduced.
Our U.S. Pat. No. 5,308,322, formerly U.S. patent application Ser. No. 08/048,906, and U.S. patent application Ser. No. 08/187,632, are hereby incorporated by reference.